I replaced my AC unit a few years ago, and went with Lennox. I couldn't be happier with it. Just as a point of comparison, the highest temperature I saw last week (during our turn at the heat wave) was 117F. This week is a more reasonable 103F-105F.

When my installer first came out to do the heat survey, we talked about what I was looking for in the system. I originally said Carrier, but he recommended Lennox. A comparable setup from Carrier would have been a few thousand dollars more (I got a new AC, air handler, and thermostat).

I can't really compare it to my previous unit, since it was around 20 years old when i got it replaced. I can say that even though the compressor is outside next to my room, it doesn't wake me up when it turns on (I'm a really light sleeper). The air handler (also Lennox) is in the attack above the closet in my room, and that doesn't wake me up either.

The only problem I've had with it in 4 years was the Smart Hub spontaneously dying. That unit controls everything, so I was without heat for a few hours until it got replaced (which wasn't a big deal). The repair guy did say that was the first hub he ever saw just die.